Some drug delivery devices may be configured to be temporarily attached to a patient to deliver a drug or other substance via an injection needle or some other means, over an extended period of time. The device may be attached to the tissue of the patient's abdomen, thigh, arm or some other portion of the patient's body.
Many of these devices have a rigid housing and may use an adhesive disposed on or over the base of the housing to adhere the device to the patient's body tissue. Many of these adhesives yield higher retention performance over an extended period of time when they are initially applied in a uniform manner with high pressure.
Applying a high uniform pressure across the adhesive, when attaching the device to the patient's body, can be difficult because body tissue is soft and often contoured or curved. Consequently, high performance retention of the device to the body over extended periods of time may not be achieved.
To overcome this difficulty, the soft body tissue may be pinched between the device and the bones or other structures behind the body tissue when attaching the device, to achieve device retention over an extended period of time. Unfortunately, pinching the soft body tissue may be uncomfortable or painful for the patient and may not uniformly apply high pressure across the adhesive.
Another method used to overcome low retention performance is to use a stronger adhesive. This method, however, increases discomfort or pain when the device is removed from the patient.
Accordingly, a drug delivery device with improved retention performance over extended periods of time and/or which allows the use of less aggressive adhesives to reduce discomfort or pain upon device removal, is desired.